Of los angeles



Jan. 27, 1931. A. LACHMAN 1,790,622

METHOD OF REFINING MINERAL OILS Filed June 22. 1927 INVEN TOR. WW

A TTORNEYS.

Patented Jan. 27, 1931 UNITED STATES PATENT OFFICE "ARTHUR LACHMAN, OF BERKELEY, CALIFORNIA, ASSIGNOR TO RICHI IELD OIL COM- PANY OF CALIFORNIA, QF LOS ANGELES, CALIFORNIA, A CORPORATION OF DELA- wean Application filed June 22,

, eral oils such as lubricatingoils, kerosene,

gasoline and shale oils, etc, and is particu larly adaptable to oils obtained by a cracking process. 'F or the purpose of simplifying the description, reference will be made to gasoline only.

Crude gasoline is usually obtamed by dis- .tillation or by cracking of crude petroleum and consists of a mixture of saturated and unsaturated hydro-carbons, together with asphaltic materials, sulphur compounds, nitrogen bases and other substances of an undefined nature. These latter substances are readily oxidizable at ordinary temperatures and are responsible for the color changes which take place when refined gasoline is stored. These oxidizable substances are re moved with difficulty'when gasoline is refined by the methods now in common use.

In order to show the nature of my mvention, it is desirable. to describe the methods now in common use in oil refinerles, and particularly that step of gasoline refining which consists in de-odorizing and stabilizing the same. Crude gasoline obtained from the stills or cracking retorts, after condensation is treated with approximately 6 to8 per cent by weight of sulphuric acid according to the nature ofthe crude gasoline. The treatment usually consists in agitating the mixture of I gasoline and sulphuric acid for an hour or more and then permitting it to settle, after which sulphuric acid sludge 1s withdrawn and the gasoline is washed with a solutlon of alkali and finally with water. Thls treatment removes most of the impurities, but a subsequent treatment is frequently necessary in order to complete the de-odorization. For this purpose a solution of sodlum plumbite is commonly employed. The general ob ections to a treatment of this character are as follbws:

v First, gasoline purified by this method is frequently subject to dlscoloratlon upon stor- 0 METHOD OF REFINING MINERAL OILS 1927. Serial No. 200,589.

age. Secondly, considerable quantities of sulphuric acid are required which are difficult to recover. Third, as much as ten per cent of the valuableh-ydrocarbons contained in the crude gasoline may be lost. Fourth, the treatment must frequently be followed with a de-odorizing process such as that .de scribed. i i

My invention consists in the discovery that the sulphuric acid normally used in refining crude gasoline may be replaced by zinc chloride and that gasoline treated with zinc chloride will be. water white, stable as to color upon exposure to' the air, and that this treatment will reduce crude gasoline losses to less than 2%.

The process briefly stated consists in treatmg gasoline or other volatile hydro-carbons by passing the same while in a vapor state through or in contact with a hot concentrated Y The gasoline so solution ofzinc chloride. treated is usually pure enough for immediate use, although it sometimes may contain small amounts of hydrogen sulphide, which may be removed by washing with a weak alkaline solution of sodium or calcium hydroxide, or

of sodium carbonate.

The strength of the zinc chloride solution is from -85%. The temperature employed is around 150 C. normally fluctuating between 145 and 155. For the purpose of describing the process in more detail, reference will be made to the accompanying drawing, which is a diagrammatic view of one form of apparatus which may be employed.

Referring to this drawing, A indicates a cracking retort or the like from which the crude, gasoline vapors discharge through the pipe-line 2. B indicates a tower of suitable height and diameter filled. with resistant mater'ial, such as firebrick'or the like indicated at 3 which forms numerous tortuous passages through the tower. Disposed above the tower or adjacent to the same is a tank containing a solution of zinc chloride having a concentration of 7 (L85 This tank is conneeted with the top of the tower by means of when the valve 5 is opened over the brickwork or resistant material. The solution then flows downward through this material finally be discharged through the and may bottom y a pipe 7, after which it is treated for recovery. The tower is also providedwith a steam or water inlet pipe 8 which intermittently or continuously supplies a predetermined amount" of water to the tower. The vapor from the still or cracking retort A enters the lower end of the tower at a point 9. It passes up through the numerous tortuous passages in the brickwork and comes into intimate contact with the zinc chloride solution travelling or flowing over the same. Both solution and vapor are maintained at -a temperature at from 145 to 155 C., and "the vapor discharges at the upper end of the is maintained 'at its predetermined limits by' a continuous introductionof water or water vapor. Otherwise solid zinc chlorlde, and

solid sludge impurities will plug the passages through which the gasoline vapors are being conducted.

It is further important that the solution of zinc chloride be saturated before it'is introduced into the systemwith zinc hydroxide or zinc oxide. ThlS may be accomplished either by agitating the solution of zinc chloride with these substances, or elseby adding to it a small amount of sodium or' calcium hydroxide.- The optimum amount of zinc oxide or hydroxide is from 1.to 3 per cent of the weightof the zinc chloride solution.

Proportions required. The reaction tower A B is kept full of zinc chloride, and zinc by droxide solution, and a fresh supply of 15 lbs. solution, more or less, is admitted for each barrel (of 42 gallons) of gasoline continuously treated; a corresponding amount of spent solution is withdrawn at the same time.

p The amount of water vapor re uired varies within rather wide limits, depending upon the concentration of the zinc chloride solution employed, the temperature at which operations are carried out and the nature and amount of inert gases which may accompany o .thegas'oline vapor being treated. For each barrel of 42 gallons of gasoline there .will be required approximately 15 pounds of concentrated zinc chloride solution, more or less,

and from 50 to 100 pounds ofwater or water vapor. During this treatment the major portion of the impurities are removed and carried out with the zinc chloride solution as a sludge, and the gasoline vapor when condensed is ready for use.. v

Having thus described my invention, what I claim and desire to secure by Letters'Patent 1S Z- 1. A method of refining mineral oils which consists in heating the oil to'form a vapor, passing the heated vapor through or in con-,

tact with a maintained aqueous solution of zinc chloride and then condensing the vapor. 2. A method of refining mineral oils which consists in heating -the oil to form avapor at a temperature of approximately150 (1., passing the heated vapor through or in con tact with an aqueous solution of zinc chloride maintained at a similar temperature and then condensing the vapor;

-3. A method of refining mineral oils which consisis in heating the oil to form a vapor at a temperature of approximately 150 (1,

passing the heated Vapor throughor in con tact with an aqueous solution of zinc chloride maintained at a similar temperature, and having a concentration of approximately 85% and then condensing the vapor.

4. A method of refining mineral oils which consists in heating the oil to form a vapor, passing the heated vapor through or in contact with a maintained aqueous solution of zinc chloride containing zinc hydroxide, and then condensing the vapor.

5. A method of refining mineral oils which consists in heating the oil to form a vapor, passing the heated vapor through or in contact with a maintained aqueous solution of zinc chloride containing from one to three per cent by Weight of zinc hydroxide, and then condensing the vapor.

6. A method of refining mineral oils which consists in heating' the oil to form a vapor, passing the heated vapor through or in contact with an aqueous solution of zinc chloride containing from one to three per cent by weight of zinc hydroxide and zinc oxide, and then condensing the vapor;

y 7. A method of refining mineral oils which consists in heating the oil to form a vapor, passing the heated vapor through or in contact with an aqueous solution of zinc chloride maintaining the solution in a fluid condition by addition of water and condensing the vapor after passing through the solution.

' 8. A method'of refining mineral oils which consists in heating the oil to form a vapor, passing the heated vapor through or in contact with an aqueous solution of zinc chloride.

containing zinc. hydroxide, maintaining the solutionin a fluid condition b addition of water and condensing the vapor after pass-v ing through the solutiqn.

9. A method of refining mineral oils which consists in heating the oil to form-a vapor,

passing the heated vapor through or in contact with an aqueous solution of zinc chloride containing from one to three per cent by Weight of zinc hydroxide and zinc oxide, maintaining the solution in a fluid condition by addition of Water and condensing the vapor after passing through the solution.

10. A method of refining mineral oils which consists in heating the oil to form a vapor, passing the heated vapor through or in contact with an aqueous solution of zinc chloride, maintaining the concentration of the solution within predetermined limits by addition of water and'condensing the vapor after passing through the solution.

11. A method of refining mineral oils which consists in heating the oil to form a vapor at a temperature of approximately (1., passing the heated vapor through or in' contact with a maintained aqueous solution of zinc chloride maintained at a similar tem perature and having a concentration of approximately 7Q85%, maintaining the concentration of the solution as specified by the continuous addition of Water, and then con- (lensing the vapor after passing through the solution.

12. A method of removing from mineral oil, materials that tend to decolorize same on standing said method including the steps of vaporizing, the oil, contacting the vapor so obtained with a zinc compound including a maintained aqueous solution of zinc chloride and condensing the resulting vapor.-

13. A method of removing matter that subsequently gives color to gasoline on standing, said method including the steps of forming a vapor from the gasoline, contacting the va por with a zinc compound including zinc chloride maintained in aqueous solution and condensing the vapor.

ARTHUR LACHMANL- 

